1. State of Art
In dry cleaning processes it is very important to separate solvents which are retained after the cleaning and centrifuging within the textiles in order to avoid pollution of the air when taking out the clothing from the machine and in order to recover the solvents. For this purpose it is known to add a drying process by drying the circulating air and following drying by fresh air. For drying the circulating air the air in the machine is circulated by a blower drawing the air from the textiles via a lint trap and pressing the air through a condenser and heating device back to the drum or basket of the machine. After a drying interval of about 10 to 20 minutes the drying process of the circulating air is followed by a drying process by fresh air which is drawn via the cleaning chamber and condenser towards a discharge or exhaust duct including an adsorber for separation of remaining solvents. Hitherto such drying process has been performed with full blower power. This is disadvantageous on account of the fact that for a time unnecessary much air is driven through the textiles, the condenser and heater and that the cooperation between recovery by condensation and adsorption is unsatisfactory. The problem is to transport during drying the circulating air by heating as much solvents as possible in a period as small as possible from the textiles towards the condenser for separating by condensation and to deodorize during drying by fresh air said textiles so that it is possible to take out the textiles essentially inodorous. The maximum output of the blower, however, is necessary only at the beginning and at the end of the drying process. Therefore, if the output of the blower is not diminished during the drying process unnecessary high energy is consumed for heating of the circulating air before its entrance into the textiles and much cooling water is consumed unecessarily for cooling the air leaving the textiles.
It has already been proposed to improve the recovery of solvents by the insertion of a water chamber within the air duct to the adsorber. However, such a water chamber generally represents a constant flow resistance and therefore is not suitable to adapt the volume of air flow to the rapidly changing concentration of solvent vapours. Furthermore, such water chamber has the disadvantage that little drops of water are drawn by the stream of air towards the adsorber and thus will diminish the effectiveness of the adsorbent material. Besides this, the separation of residuals of solvents by fresh air during the fresh air drying period is handicaped and the expenditure of time is highly increased without any benefit.
2. Problem
The main problem of the present invention is to provide a method and apparatus as outlined above which may guarantee an optimal drying and recovery process with low expenditure of energy and time.